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1.
Johnsson  R. 《Hydrobiologia》2001,(1):427-430
A new species of Acontiophorus belonging to the family Asterocheridae was found in Ushuaia, Patagonia, southern Argentina. The new species is distinctive in having 9-segmented antennule, five setae on terminal endopodal segment of leg 1, seven elements on terminal segment of leg 1 and leg 4 exopods, and characteristic setation on maxillule lobes. This combination of characteristic features does not occur in any other species of the genus. The genus Acontiophorus is recorded for the first time from the South Atlantic.  相似文献   

2.
A new species of cyclopoid copepod, Ochridacyclops nipponensis is described from Japan. This is the third species of the genus. The type material was collected from small streams in the mountainous regions in Shikoku. The new species can easily be distinguished from other members of genus by its 12-segmented antennule, by the proportional length of genital double-somite relative to the length of 3 free abdominal somites, and by the shape of caudal rami. The male is unknown.  相似文献   

3.
M. Alonso 《Hydrobiologia》1985,128(3):217-228
A very particular form of Daphnia (Ctenodaphnia), adapted to life in epicontinental hyperhaline waters of Mediterranean arid regions had long been confused with Daphnia (Ctenodaphnia) dolichocephala Sars, 1895. In this paper the morphological and ecological differences between the two taxa are pointed out and comparison is made with another closely related Rumanian form (Daphnia cf. mediterranea) and with the related Spanish species (D. atkinsoni and D. chevreuxi). The Daphnia of saline environments is described here as Daphnia (Ctenodaphnia) mediterranea. The most important differential characters of this new species are: 1) the short and widely rounded rostrum; 2) dorsal ridge of the female extends to the anteriormost part of the head; 3) elliptical ephippium with a ride anterior margin; convex shape and separate from the dorsal ridge; 4) males possessing a very long antennule base that reaches the distal limit of the head.  相似文献   

4.
The six naupliar stages of Cyclopina yutimaete Lotufo are described and compared to other cyclopoid nauplii. They seem more similar to freshwater cyclopoid nauplii than to marine species. The hirsute aspect of the last segment of the antennule is of diagnostic value for these nauplii.  相似文献   

5.
Cyclopoid copepods are common in lakes and ponds, and they have a significant predation impact on the communities of the small zooplankton species. To reduce the predation risk, some cladoceran zooplankters develop protuberant (defensive) morphologies in the presence of the copepods. In the case of the small cladoceran Bosmina, they elongate their appendages (antennule and mucrone) and change the antennule morphotype. However, information about the effectiveness of these defensive devices against copepod predation is still insufficient. In our study, to find the compositive effects of these appendages on the vulnerability of Bosmina, we exposed two bosminid species (B. longirostris and B. fatalis) of different body sizes and with appendages of different lengths and shapes to copepod (Mesocyclops) predation. The experiment revealed that the shape of the antennule is a main factor determining the bosminid’s vulnerability to copepod predation and indicated that the protection of the opened ventral carapace must be a key strategy by which Bosmina avoids copepod predation.  相似文献   

6.
A population of cyclomorphic Bosmina coregoni was studied in Lake Östersjön, southwestern Sweden and results from field samples collected in 1988, 1989, 1990 and 1991 are presented. Animals collected in summer have remarkably higher carapace and prolonged antennule compared to what we call the normal morph. In 1991 the extreme morph reach its maximum body length, body height and antennule length in July to September. The occurrence of the extreme morph coincide with the hatching of the predaceous cladoceran Leptodora kindtii.The two morphs fluctuate in abundance and in relation to each other. In early spring only the normal morph occurred in the samples followed by a period of about two months when the two morphs were found together, in July only the extreme morph was found. In September the two morphs were again present in the lake. As has been shown for other cladoceran, the conspicuous carapace and antennule could be an adaptive response that decreases mortality due to invertebrate predation. Spectacular features like these are likely also accompanied by some sort of costs.  相似文献   

7.
Hanamura  Yukio  Kase  Tomoki 《Hydrobiologia》2003,497(1-3):145-152
A new species of Palaumysis, P. pilifera, the fourth species of the genus, is reported from two submarine caves of Okinawa, southwestern Japan. The new species closely resemble the two species previously reported from the Pacific by possessing a multi-segmented inner flagellum in the antennule, but it differs from them in having the terminal spine of the male fourth pleopod bearing rows of fine setules (or hairs) near midlength, as opposed to a naked spine in the latter two species. The present discovery extends the geographical limit of the genus further north to 26° N in the western North Pacific. Additional information on the colour pattern and ecological feature of P. simonae Bcescu & Iliffe, 1986, are provided on the basis of newly collected material from a submarine cave on Palau.  相似文献   

8.
Jankowski  Thomas 《Hydrobiologia》2004,530(1-3):521-528
Invertebrate predators may cause strong changes in behaviour, life-history, and morphology of prey species. However, little is known about the influence of jellyfish on such characteristics of their prey. This study analyses the impacts of the freshwater jellyfish Craspedacusta sowerbii on life history and morphological defenses in a population of the cladoceran Bosmina longirostris . Length of mucro and antennule, size-dependent number of eggs, size at maturity, and size of juveniles, adults, and egg-carrying females were investigated during a 23 days experiment using medusae-enriched and control enclosures filled with natural plankton populations. Significant differences in parameters investigated were found not only between treatments, but also within treatments over time. Changes in Bosmina life-history parameters and morphology in controls were probably due to predation by cyclopoid copepods. The significant increase in the size of adults and egg-carrying females as well as the increase in mucro and antennule length in medusae-enriched enclosures are discussed as defense strategies against the freshwater jellyfish.  相似文献   

9.
A new genus (Celsinotum) and three new species are described from intermittent athalassic saline waters in the Paroo region of northwest New South Wales, which have TDS varying from 2.8 to 14.0 g l-1. The species are large, thin, high-bodied, and have a pronounced keel on the shell but not on the head. The marginal armature of the postabdomen consists entirely of clusters of fine spinules. Most strikingly, the males have 12 terminal aesthetascs on the antennule, and in addition have 5 or 6 equally long accessory aesthetascs arising laterally. Alona taraporevalae from India presumably also has this character, but a comparison of the two species indicates they are not closely related.The taxa bear a general similarity to Alona diaphana from Australia, but a close comparison shows that they, too, are unrelated. A. diaphana has a prominent spine arising from the basal segment of the antennal exopod, the two IDL (= inner distal lobe) setae on trunklimb I have a much coarser setulation distally than in Celsinotum, and on the postabdomen the postanal portion is always considerably longer than the anal, and the marginal armament consists of single setae distally and clusters of only a few setae proximally. Besides, the species is smaller, the body is wider and less high, and the shell although weakly ridged is not keeled. The male has 9 terminal aesthetascs and no accessory lateral ones.In athalassic saline waters around the world the number of anomopod species declines negative exponentially in relation to salinity. Many of the freshwater species persist into the 3 to 10 range without any difficulty, some occur in abundance up to 30, and a few even extend into the hypersaline range. Chydorids, though, except for a very few species, do not tolerate salinities higher than about 15, and none of them seem adapted to these salinities and confined to them. Celsinotum, though, possibly is so adapted, as it did not occur in other basins of the region with lower salinities, and it is not presently known from other regions.Having different but closely related congeneric taxa in nearby lakes of the same region seems surprising. The three species of Celsinotum are very similar in most details of morphology, but they vary significantly in body proportions, the number of denticle clusters on the postanal portion of the postabdomen, and in such seemingly minor details as the amount of expansion of the labral plate. Such taxonomic differentiation, which has been observed in other groups of organisms as well, is believed to have arisen from the extreme temporal isolation of these waterbodies, those in the Paroo region normally containing water only once every 5 to 20 years.  相似文献   

10.
Y. Ranga Reddy 《Hydrobiologia》2002,470(1-3):37-43
A new species of the genus Habrobathynella Schminke, 1973, i.e. H. nagarjunai n.sp., is described from the groundwater of the Nagarjuna University campus near Guntur town, South India. One of the principal criteria in the original definition of Habrobathynella is amended to accommodate the new species. H. nagarjunai n.sp. differs from its three congeners, i.e. H. milloti (Delamare & Paulian, 1954), H. jeanneli (Delamare & Paulian, 1954) from Madagascar, and H. schminkei Reddy, 2002 from India, in several essential morphological details: the sympodite of uropod bears 8–10 similar spines; the apophysis on segment 4 of the antennule is short; of the two setae on the exopodite of uropod, one is apical and the other subapical in position; the basal segment of maxilla has three unequal setae; the male thoracopod VIII is relatively elongate. H. nagarjunai n. sp. is the second representative of the groundwater (eustygobiont) Bathynellacea in South Asia. Furthermore, a key to the identification of Habrobathynella spp. is given.  相似文献   

11.
We used RAPDs (Random Amplified Polymorphic DNA) to test genetic divergence between two populations of Bosmina spp. in Lake Östersjön, Sweden. Previous taxonomic studies on European species within the genus Bosmina have been based on morphological characters alone. RAPD markers distinguished the two populations and supported the specific status of B. coregoni and B. longispina based on morphological characters. Furthermore, juveniles with a long antennule and a mucro were classified as B. coregoni. RAPDs also revealed genetic differences among the tested individuals, suggesting several clones within each species.  相似文献   

12.
Ooishi  S.  Illg  P. L. 《Hydrobiologia》1988,167(1):561-566
In taxonomic studies (in preparation) of the genus Botryllophilus from the eastern and western coastal waters of the Pacific and from the northern Gulf of California, we have found that the females are morphologically divided into 2 types. The 2 morpho-types in our material, which includes 10 species, are characterized by features of the urosome including anal segment and caudal rami, rostrum, antennule, antenna, mandible, maxillule, maxilla, maxilliped, 1st to 5th legs, and the apparatus at the oviducal aperture. These characters are described and the significance of the recognition of the 2 morpho-types is discussed for the purpose of solving taxonomic problems in Botryllophilus.  相似文献   

13.
A Ceriodaphnia has been found inWaterbodies of the plains and foothills of Uzbekistan and southern Kazakhstan that strongly resembles C. reticulata (Jurine, 1820). The female of this new species, C. turkestanica, differs from C. reticulata because it lacks a fenestra (nucal organ) in the cervical notch of the adult, has a rostral pore encircled by a ridge of cuticle rather than opening on the flat surface of a polygon anterior to the antennules, and has fewer and finer spines punctuating the row of fine spinules along the inner margin of the posterior carapace. The locule of the ephippium lacks the regular, small, rounded protuberances seen in the locule of C. reticulata. The male of C. turkestanica also exhibits the lack of a cervical fenestra, an encircled rostral pore, and variable, fine spines along the posterior carapace inner margin. In addition, it has a much shorter terminal seta on the antennule, and increasing lengths of the spinose setae on endites 1–3 of trunk limb I rather than the second being the longest as in C. reticulata. Because of similarities between these species, we suggest that C. turkestanica either is derived from C. reticulata or that the two share a common ancestor.  相似文献   

14.
A succession of morphs from Bosmina coregoni f. coregoni to B. c. f. thersites, which vary in shell and antennule characters, occurred in an undated 176 cm long sediment core from the Neversdorfer See (N. Germany).  相似文献   

15.
A new genus of the harpacticoid family Laophontidae is described and named Peltidiphonte gen. n. Eight new species are assigned to this genus; they were collected from different locations in the Indo-West Pacific Ocean, including the Comoros, the Kenyan coast, the Red Sea, the Andaman Islands, the northern coast of Papua New Guinea, the Solomon Islands and the northeastern coast of Australia. Most of the specimens were collected from dead coral substrates, suggesting a close affinity between the members of the new genus and this substrate. Peltidiphonte gen. n. can easily be discriminated from other genera of the family by the extremely depressed body and by the shape of the antennule, bearing two (or three) processes on the first segment and a hook-like process along the outer margin of the second segment. An identification key for the new genus is provided.  相似文献   

16.
The tribal name Bocageeae Endlicher is reestablished and the tribe is circumscribed on the basis of solitary internodal ebracteate pedicels that are articulated at the base, and pollen shed in polyads of eight or more grains. Septate anther locules, large pollen size, and seed appendages are prevalent in the tribe. Intectate pollen with free-standing columellae, rare in Annonaceae, occurs not only in the genusTrigynaea but also in some species ofBocagea andHornschuchia. As defined here, the Bocageeae include seven neotropical genera:Cymbopetalum, Porcelia, Bocagea, Cardiopetalum, Froesiodendron, Hornschuchia, andTrigynaea. The latter five genera are revised and the treatments include ten new species:Cardiopetalum plicatum, Froesiodendron urceocalyx, Hornschuchia lianarum, H. santosii, H. leptandra, Trigynaea cinnamomea, T. lanceipetala, T. triplinervis, T. lagaropoda, andT. axilliflora, all from tropical South America. A new combination,Froesiodendron longicuspe, changes the rank of that taxon from subspecies to species.Cardiopetalum surinamense is removed fromFroesiodendron and reassigned toCardiopetalum on the basis of its connate petals, dehiscent monocarps, and seeds with bilobed arils. A cladogram provides an explicit hypothesis of intergeneric relationships in the tribe. The new combinationOnychopetalum periquino, based onTrigynaea periquino, is made.  相似文献   

17.
Six nauplius and five copepodid stages as well as adults ofParalabidocera antarctica (I. C. Thompson, 1898) (Copepoda:Calanoida) are described based on specimens obtained from fast ice and collected by a plankton net near Syowa Station (69°00 S, 39° 35 E), Antarctica. The adult male and female are redescribed in detail. Nauplius stages ofP. antarctica are very similar to the previously describedAcartia species. Sexual dimorphism becomes apparent from copepodid IV onwards in the morphology of antennule and leg 5. The copepodid stages of this species retain certain characteristics not only of Acartiidae but also of Pontellidae and Parapontellidae.  相似文献   

18.
The adult morphology of the Australian Limnadopsis shows some remarkable differences to that of other Limnadiidae. These differences are not reflected in its larval development. In Limnadopsis parvispinus, larval development comprises six stages. In stages I and II only the three naupliar appendages are present: the antennule as a small bud, the biramous antenna as the main swimming organ, and the mandible. The antennal protopod bears two endites, the proximal naupliar process and a more distal endite. In stage III a bifid naupliar process (in earlier stages not bifid) and the first signs of the carapace and trunk limb anlagen (undifferentiated rudiments) appear. In stage IV the carapace anlagen become more pronounced. The number of trunk limb anlagens increases to five, and differentiation has commenced. In stage V the first five pairs of trunk limbs are differentiated to varying degrees. The anterior-most four pairs of trunk limbs are subdivided into five endites, a small endopod, an exopod and an epipod. The bivalved carapace covers the anterior-most limbs. In larval stage VI the carapace is larger and the trunk limbs are further differentiated. A general pattern in the sequence of larval stages is the increasing number of sensilla on the antennules. From the last larval to the first postlarval stage, a significant change in morphology takes place. The trunk limbs are now used for swimming. Typical larval organs are much smaller than in the last larval stage. A comparison with other representatives of the Limnadiidae shows a high degree of correspondence, with most differences explained by the heterochronous appearance of characters during development. Five to seven stages are described for all studied Limnadiidae, including one particular stage in which four fully developed setae, a bifid naupliar process and the first signs of carapace anlagen are present. These characters are found in stage III in L. parvispinus, Limnadia stanleyana, Eulimnadia texana, and Imnadia yeyetta but in stage IV in E. braueriana and L. lenticularis. Based on a comparison of the larval stages of six limnadiid and one cyzicid species, we conclude that at least six naupliar stages belong to the limnadiid ground pattern.  相似文献   

19.
The endemic New Guinean genusIschnea F. Muell. (Asteraceae, Senecioneae, Blennospermatinae) is revised and four species are recognized. Characters of special interest are tubeless ray florets, male disc florets, and secretory spaces in leaves. A principal component analysis is made on theIschnea elachoglossa F. Muell. complex which shows great variation. One new species,I. capellana Swenson, from the Star Mountains, is described. A key, illustrations, and distribution maps to all species are supplied.  相似文献   

20.
Taxonomy of the genus Cristulariella is revised, retaining Cristulariella (Crist.) depraedans as the type. Two new species, Crist. cercidiphylli and Crist. corni, are additionally described under the genus. The new anamorphic genus Hinomyces is erected to accommodate Botrytis (Cristulariella) moricola and Cristulariella pruni. A new genus and species, Nervostroma depraedans, is erected in the Sclerotiniaceae to accommodate the teleomorph of Crist. depraedans, with an additional species, Nervostroma cercidiphylli.  相似文献   

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